1. Field
The present disclosure relates to a device and a method for detecting a biomolecule using a nucleic acid aptamer.
2. Description of the Related Art
Aptamers are single-stranded DNA or RNA molecules isolated and obtained from oligomers that bind to a specific chemical or biological molecule with high affinity and selectivity. They have been used for detection of biomolecules. Since the aptamers are based on oligonucleotides, they have many advantages over protein-based antibodies. That is to say, they can be obtained ex vivo and a variety of organic and inorganic substances may be used as target molecules. In addition, once a specific aptamer binding specifically to a specific target molecule is identified, it can be produced in large scale at low cost.
However, although the aptamer can recognize the target molecule, it cannot provide signals reporting the binding with the target molecule. Thus, it is needed to develop a method for complementing these properties of the aptamer and maximizing its function as a probe molecule.
A method of using a cantilever for detecting biomolecules has been developed (Korean Patent Publication No. 10-2011-0055930). In this method, a cantilever sensor and a DNA aptamer immobilized on the cantilever are used to detect thrombin. Therefore, a method allowing for convenient detection of a biomolecule using an aptamer without using the cantilever is needed.
Although quantum dot was discovered in the 1970s, it has been used in the field of life science for only 4-5 years. A quantum dot consisting of a CdSe core and a ZnS shell is a spherical material with a diameter ranging from several nanometers to tens of nanometers. Since it emits fluorescence of different wavelength according to the particle size, the quantum dot can be utilized variously in basic life sciences such as cell biology as well as in applied life sciences such as protein chips and biosensors. The quantum dot is excitable with light of various wavelengths from UV to red light and has a narrow, adjustable emission spectrum. Being an inorganic material, it is stable against chemical reactions and can be easily bound to a biomaterial through surface treatment. In addition, since the quantum dot has superior optical stability and can be monitored continuously in real time, it is an attractive material in the field of biosensors. However, its use in biosensors has been limited since the quantum yield of light emission decreases significantly when the quantum dot is changed from the hydrophobic form to the hydrophilic form or when it is included in other materials.
A method of detecting multiple proteins by immobilizing aptamers for the target proteins on quantum dots with different emission values was developed (Matthew et al. Chem Bio Chem 2005, 6, 2163-2166). This method is problematic in that quantification of the detected proteins is difficult, a high-sensitivity fluorescence detector is required for detection of fluorescence, and an accurate control of the flow channel is necessary. In addition, the analysis time tends to be long and a large amount of sample is needed.
Also, there was developed an aptamer-based sandwich analysis method based on sandwich ELISA for quantification (Yolanda et al. Anal. Chem. 2010, 82, 5591-5597) and fluorescence analysis using aptamers for detection of proteins. This method is problematic in that the analysis protocol is very complicated and two or more epitopes are required for the target protein.